A manufacturer of aluminum doors currently is able to sell 400 doors per week at a price of $78 each. If the price were lowered to $60 eachr an additional 7'0 doors per week could he sold Estimate the current elasticity of demand for the doorsr and also estimate the current value of the manufacturer's marginalrevenue function. The elasticity of demand for the doors is approximately . (Type an integer or a decimal. Do not round until the nal answer. Then round to the nearest hundredth as needed.)